InputStreamReader笔记

InputStream

IputStream 字节输入流-抽象父类-不可实例化
FileIputStream 操作文件的字节输入流-普通子类
FileIputStream（File file）
FileIputStream(String pathName)
BufferedInputStream 子类
BufferedInputStream 高效字节输入流-普通子类
BufferedInputStream(InputStream in)
由于抽向父类不可实例化，所以传入的参数是FIS(FileInputStream)
BIS（BufferedInputStream）缩写同

read()每次调用都会读取一个字节，如果读到了末尾，返回值是-1
TIPS:读取时需要设置变量保存读取的结果，否则数据读取不完全
流使用完毕后必须关闭【.close】，而且必须写在finally{}中，确保关流操作时一定会执行的
finally{}是try-catch结构的第三个部分，这个部分不论是否捕获到异常，一定会执行

IputStream测试

package cn.tedu.file;import java.io.*;//本类用于练习字节输入流
public class TestIn {public static void main(String[] args) {
//        method();method2();}private static void method2() {InputStream in =null;try {
//            InputStream in = new BufferedInputStream(
//                    new FileInputStream(new File("D:\\read\\1.txt")));in = new BufferedInputStream(new FileInputStream("D:\\read\\1.txt"));int b;while ((b=in.read())!=-1){System.out.println(b);}} catch (Exception e) {//关流操作卸载finally中e.printStackTrace();}finally {try {in.close();} catch (IOException e) {e.printStackTrace();}}}private static void method() {//创建一个在本方法中生效的变量，注意手动初始化InputStream in = null;
//        InputStream in = new InputStream();try {
//            InputStream in = new FileInputStream(new File("D:\\read\\1.txt"));in = new FileInputStream("D:\\read\\1.txt");/*read()每次调用都会读取一个字节，如果读到了数据的末尾，返回-1*/
//            System.out.println(in.read());
//            System.out.println(in.read());
//            System.out.println(in.read());
//            System.out.println(in.read());
//            System.out.println(in.read());
//            System.out.println(in.read());
//            System.out.println(in.read());
//            System.out.println(in.read());int b;while ((b=in.read())!=-1){System.out.println(b);}} catch (Exception e) {e.printStackTrace();/*try-catch结构中的第三个部分：finally* 这部分不论是否捕获到异常，是一定会被执行到的代码，常用于关流*/}finally {try {in.close();} catch (IOException e) {e.printStackTrace();}}}
}

字符输入流

抽象父类：
Reader字符输入流-抽象父类-不可实例化
FileReader-文件字符输入流-普通子类
FileReader(File file)/FileReader(String pathName)
BufferedReader-高效字符输入流（缓冲字符输入流）-普通子类
BufferedReader(Reader in) 一般使用时传入的是Reader的子类

Reader测试

package cn.tedu.file;import com.sun.org.apache.xerces.internal.dom.DeferredEntityReferenceImpl;import java.io.*;//本类用于测试字符流的读取
public class TestIn2 {public static void main(String[] args) {
//        method();method2();}private static void method() {Reader in = null;
//        Reader in =new Reader();try {
//                in = new FileReader(new File("D:\\read\\1.txt"));in = new FileReader("D:\\read\\1.txt");
//                System.out.println(in.read());int b;while((b=in.read())!=-1){System.out.println(b);}System.out.println();} catch (Exception e) {e.printStackTrace();}finally {try {in.close();} catch (IOException e) {e.printStackTrace();}}}private static void method2() {Reader in = null;try{in = new BufferedReader(new FileReader("D:\\read\\1.txt"));int c ;while((c=in.read())!=-1){System.out.println(c);}}catch(Exception e){e.printStackTrace();}finally {try {in.close();} catch (IOException e) {e.printStackTrace();}}}
}

OutputStream

OutputStream 字节输出流-抽象父类-不可实例化
FileOutputStream 操作文件的字节输出流-普通子类
FileOutputStream（File file）
FileOutputStream(String pathName)
BufferedOutputStream 子类
BufferedOutputStream 高效字节输出流-普通子类
BufferedOutputStream(InputStream out)
由于抽象父类不可实例化，所以写出的参数是FOS(FileOutputStream)
BOS(BufferedOutputStream)
TIPS：append表示输出内容是否追加，默认为false不追加，改为true则追加

OutputStream测试

package cn.tedu.file;import java.io.*;//本类用于测试字节输出流
public class TestOut {public static void main(String[] args) {
//        method();method1();}private static void method() {OutputStream out = null;try {out = new FileOutputStream(new File("D:\\read\\1.txt"));out.write(45230);out.write(160);out.write(133);} catch (Exception e) {e.printStackTrace();}finally {try {out.close();} catch (IOException e) {e.printStackTrace();}}}private static void method1() {OutputStream out =null;try {out = new BufferedOutputStream(new FileOutputStream("D:\\read\\1.txt"));out.write(123);out.write(111);out.write(101);} catch (Exception e) {e.printStackTrace();}finally {try {out.close();} catch (IOException e) {e.printStackTrace();   }}}
}

字符输出流

抽象父类：
Writer字符输出流-抽象父类-不可实例化
FileWriter-文件字符输出流-普通子类
FileWriter(File file)/FileWriter(String pathName)
BufferedWriter-高效字符输出流（缓冲字符输出流）-普通子类
BufferedWriter(Writer out) 一般使用时传入的是Writer的子类

Writer测试

package cn.tedu.file;import java.io.*;//本类用于测试字符输出流
public class TestOut2 {public static void main(String[] args) {
//        method();method2();}private static void method() {FileWriter f =null;try {f = new FileWriter("D:\\read\\1.txt");f.write(97);f.write(98);f.write(99);} catch (IOException e) {e.printStackTrace();}finally {try {f.close();} catch (IOException e) {e.printStackTrace();}}}private static void method2() {BufferedWriter out =null;try {out = new BufferedWriter(new FileWriter("D:\\read\\1.txt",true));out.write(99);out.write(99);out.write(99);} catch (Exception e) {e.printStackTrace();}finally {try {out.close();} catch (IOException e) {e.printStackTrace();}}}
}